Device for separating a mixture of fine and coarse material particles



Sept.'27, 1938. A. MULLER I 2,131,451 DEVICE FOR SEPARATING A MIXTURE OFFINE AND GOA ESE MATERIAL PARTICLES Filed April 16, 1936 I ##arneysPatented Sept. 27, 1938 PATENT- OFFICE DEVICE FOR SEPARATING A MIXTUREOF FINE AND COARSE MATERIAL PARTICLES Adolf Miiller, Niedersediltz, nearDresden,

Germany Application April 16, 1936, Serial No. 74,674

In Germany April 26, 1935 2 Claims.

This invention relates to a device for separating a mixture of fine andcoarse particles of material by means of an air current, by which theparticles are entrained, and a separating wheel 3 rotating transverselyof said current within a separating chamber having inlet and outletopenings but otherwise closed.

Devices of this kind are already known. In the known constructions theseparating wheel which is to remove the coarse material as completely aspossible from the mixture entrained by the air current is equipped withpaddle-like blades; or, in lieu of paddles, it ha been proposed toprovide the separating wheel with impact bodies consisting of bars,chains, ropes or the like. In no case has the precise separation or thecoarse material from the fine material been obtained. In the firstplace, trouble is caused by an additional air current like that producedby a fan which is set up by the wheel blades, whether of fiat form or ofbar form, rotating at high speed, as compared to the speed of the mainair current. This interferes with the separating action or theseparating wheel, and prevents the exact adJustment of the grade ofseparating by altering the speed of the air current or the number ofrotations of the wheel. A second objection is that the blades are reliedon to eiiect separating over their entire radial dimensions, and,consequently, difierent parts of the blades rotating at difiel'entperipheral speeds, depending on the radial distance from the axis ofrotation, come into play in the separating operation and confuse thesetting of the separating limit.

,According to the invention, these drawbacks are substantially avoidedby reason that there is employed for separating only a narrow annularzone of the separating wheel. Accordingly, of the several annular zonesof the wheel having substantially difier'ent peripheral speeds therecomes into action only a single narrow zone which for practical purposesmay be egarded as rotating at one speed. In order to obtain the maximumseparating action from a given size of separating wheel the inletopening in the siftin wheel casing necessary for the air current doesnot extend over the entire circumference of a circle so as to form acomplete annular slot, but the cross section of the inlet opening isformed in the shape of a segment of an annulus registering with theannular zone of the separating wheel, of such width as to avoidrestriction oi! the air flow by excessiv contraction oi. the opening.

(c1. 2oa-144) An embodimentof the invention is illustrateddiagrammatically in the accompanying drawing in which Fig. 1 is a.vertical longitudinal section on the line A-B of Fig. 2; Fig. 2 is an.end view.

Of the supply conduit i for the current of air 5 by which the materialis entrained there is shown only the upper portion with the mouthpiece 2having an arcuate termination which leads into the correspondinglyformed inlet opening in the separating wheel casing 3. The separatingwheel 4 allows the fine material to enter between the blades 5.in thedirection of the arrow 6 into a chamber 1, part only of which is shown,to dep sit therein, while the coarse material separated from the finematerial collects in the lower part of the separating wheel casing 3 andis discharged in known manner by a slowly rotating wheel 8 presentingcompartments. The blades 5 do not only extend away from the hub to whichthey are attached at an angle to an imaginary radius of such hub and ina direction opposite to that of their rotation, but they are slightlycurved, being convex on their forwardly-progressing .faces. Thisconstruction-increases the force with which the particles are shoved tothe 25 perimeter of the wheel as they progress toward such perimeter.

What I claim is: 1. In a device of the character described, a source ofsupply of mixed air and fine and coarse '3 particles, a rotatableseparating wheel with transverse curved blades curving away from theaxis of said wheel in a direction opposite to that of their rotation,and means adapted, to direct said supply between said blades in a narrowzone near the perimeter of said wheel, said directing means beingsubstantially a section of an annulus in cross-area, the geometriccenter of said annulus-substantially coinciding with the axis of saidwheel.

2. A device for separating materials comprising a stationary housing, arotating separating wheel carrying transversely extending blades mountedin said casing, means for supplying a mixture of air and fine and coarsematerial to said separating wheel and for causing said air to flowthrough said separating wheel in an axial direction, said supply meansincluding a slot in said housing near the Per phery ot'said wheel and aconduit connecting with said slot, said slot and the' adlacent portionof said conduit being in the form of a segment of a narrow annulusconcentric wi h the axis of said wheel.

ADOLF MfiILER.

